Can lab experiments on student populations serve to identify the motivational forces present in society at large? We address this question by conducting, to our knowledge, the first study of social preferences that brings a nationally representative population into the lab, and we compare their behavior to the behavior of different student populations. Our study shows that students may not be informative of the role of social preferences in the broader population. We find that the representative participants differ fundamentally from students both in their level of selfishness and in the relative importance assigned to different moral motives. It is also interesting to note that while we do not find any substantial gender differences among the students, males and females in the representative group differ fundamentally in their moral motivation.